At least five U.S. Secret Service officials involved in the planning of former President Donald Trump’s ill-fated July 13 campaign rally in Butler, Pennsylvania, have been placed on administrative duty.

At least five Secret Service officials involved in planning Trump’s July 13 rally in Butler, where the 45th president was shot in the ear by gunman Thomas Matthew Crooks, have been put on administrative duty, two sources familiar with the situation told ABC News.

WATCH — Col. John Mills: Trump Was Getting “Economy” Level of Security from Secret Service:

The Secret Service officials are still allowed to work, but they are prohibited from being involved in anything operational, such as security planning, the sources added.

The agency’s Office of Professional Responsibility investigation has reportedly expanded to not only the failures involving July 13, but also the classified threats against President Trump by Iran, and what the Secret Service did in response.

A Secret Service official told the outlet that more senior officials could get caught up in the probe.

“The U.S. Secret Service is committed to investigating the decisions and actions of personnel related to the event in Butler, Pennsylvania and the attempted assassination of former President Donald Trump,” the agency said, adding that its “mission assurance review is progressing.”

“We are examining the processes, procedures and factors that led to this operational failure,” the Secret Service said.

WATCH — Trump Praises Female Secret Service Agent Who Shielded Him:

As Breitbart News reported, the agency has faced heavy backlash in response to the July 13 assassination attempt against President Trump, which resulted in the death of former fire chief Corey Comperatore and two other rallygoers, David Dutch and James Copenhaver, becoming severely injured.

Ten days after the assassination attempt, Secret Service Director Kimberly Cheatle resigned following a scathing congressional hearing in which she was unable or unwilling to answer many key questions from lawmakers on the agency’s failure to protect President Trump.

The Secret Service has since been placing bulletproof glass around President Trump’s podium during outdoor rallies, sources told ABC News.

Alana Mastrangelo is a reporter for Breitbart News. You can follow her on Facebook and X at @ARmastrangelo, and on Instagram.